Unverified Commit 7cb537b6 authored by Al Viro's avatar Al Viro Committed by Christian Brauner
Browse files

file: massage cleanup of files that failed to open 



A file that has never gotten FMODE_OPENED will never have RCU-accessed
references, its final fput() is equivalent to file_free() and if it
doesn't have FMODE_BACKING either, it can be done from any context and
won't need task_work treatment.

Now that we have SLAB_TYPESAFE_BY_RCU we can simplify this and have
other callers benefit. All of that can be achieved easier is to make
fput() recoginze that case and call file_free() directly.

No need to introduce a special primitive for that. It also allowed
things like failing dentry_open() could benefit from that as well.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
[Christian Brauner <brauner@kernel.org>: massage commit message]
Link: https://lore.kernel.org/r/20231126020834.GC38156@ZenIV


Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent b85ea95d

fs/file_table.c

+4 −12
Original line number Diff line number Diff line
@@ -75,18 +75,6 @@ static inline void file_free(struct file *f) 
	}

}



void release_empty_file(struct file *f)

{

	WARN_ON_ONCE(f->f_mode & (FMODE_BACKING | FMODE_OPENED));

	if (atomic_long_dec_and_test(&f->f_count)) {

		security_file_free(f);

		put_cred(f->f_cred);

		if (likely(!(f->f_mode & FMODE_NOACCOUNT)))

			percpu_counter_dec(&nr_files);

		kmem_cache_free(filp_cachep, f);

	}

}



/*

 * Return the total number of open files in the system

 */
@@ -445,6 +433,10 @@ void fput(struct file *file) 
	if (atomic_long_dec_and_test(&file->f_count)) {

		struct task_struct *task = current;



		if (unlikely(!(file->f_mode & (FMODE_BACKING | FMODE_OPENED)))) {

			file_free(file);

			return;

		}

		if (likely(!in_interrupt() && !(task->flags & PF_KTHREAD))) {

			init_task_work(&file->f_rcuhead, ____fput);

			if (!task_work_add(task, &file->f_rcuhead, TWA_RESUME))

fs/internal.h

+0 −1
Original line number Diff line number Diff line
@@ -94,7 +94,6 @@ extern void chroot_fs_refs(const struct path *, const struct path *); 
struct file *alloc_empty_file(int flags, const struct cred *cred);

struct file *alloc_empty_file_noaccount(int flags, const struct cred *cred);

struct file *alloc_empty_backing_file(int flags, const struct cred *cred);

void release_empty_file(struct file *f);



static inline void file_put_write_access(struct file *file)

{

fs/namei.c

+1 −4
Original line number Diff line number Diff line
@@ -3785,10 +3785,7 @@ static struct file *path_openat(struct nameidata *nd, 
		WARN_ON(1);

		error = -EINVAL;

	}

	if (unlikely(file->f_mode & FMODE_OPENED))

	fput(file);

	else

		release_empty_file(file);

	if (error == -EOPENSTALE) {

		if (flags & LOOKUP_RCU)

			error = -ECHILD;